function [ ratio ] = compressionRatio()
 
    [filename, user_canceled] = imgetfile;
    if user_canceled
        return;
    end
   
    info = imfinfo(filename);
    
    compressedSize = info.FileSize;
    realSize = info.Width * info.Height * info.BitDepth / 8;
    ratio = compressedSize / realSize; 
end

